Complete mitochondrial genome of the Bewick's swanCygnus columbianus bewickii(Aves, Anseriformes, Anatidae)

Optimised PCR assays for detecting elusive waterfowl from environmental DNA

For many aquatic and semiaquatic mammal, amphibian and fish species, environmental DNA (eDNA) methods are employed to detect species distribution and to monitor their presence, but eDNA is much less employed for avian species. Here, we developed primers for the detection of true geese and swan species using eDNA and optimised a PCR protocol for eDNA. We selected taiga bean goose (Anser fabalis fabalis) as our focal (sub)species and sampled water from lakes, from which the presence of taiga bean goose was visually confirmed. To test, if taiga bean goose DNA could be detected among DNA of other goose species, we similarly sampled eDNA from a zoo pond housing several Anatidae species. We were able to detect taiga bean goose DNA in all but one of the tested lakes, including the zoo pond. The primers developed are not species-specific, but rather specific to the genus Anser, due to the close relatedness of Anser species, which prevented the development of species-specific primers and the use of, for example, quantitative PCR. We also developed eDNA primers for Branta species and Cygnus species and tested these primers using the same samples. Canada goose (B. canadensis) and barnacle goose (B. leucopsis) DNA were only detected in the zoo pond (in which they were present), as the sampled natural lakes fall outside the range of these species. We detected whooper swan (C. cygnus) DNA in three lakes and the zoo pond (in which the species was present). The eDNA method presented here provides a potential means to monitor elusive goose species and to study the co-occurrence of large waterfowl.

The complete mitochondrial genome of Anser indicus (Aves, Anseriformes, Anatidae)

The bar-headed goose is known one of the world's highest-flying birds. In this study, the complete mitochondrial genome of Anser indicus (16,728 bp in length) was sequenced. Similar to the typical mtDNA of other vertebrates, goose mtDNA contained 37 genes (13 protein-coding genes, 2 rRNA genes and 22 tRNA genes) and a non-coding region (D-loop). The characteristics of the mitochondrial genome were analyzed in detail. We deduce that ND5 may be a major gene required for adaptation to high-altitude flight. The complete mitochondrial genome sequence of A. indicus obtained will be useful for phylogenetics, and biological characteristics.

Complete mitochondrial genome of Tundra swan Cygnus columbianus jankowskii (Anseriformes: Anatidae)

Cygnus columbianus jankowskii is a subspecies of Tundra swan, which breeds in eastern Russia and northeast China, wintering in the middle and lower reaches of the Yangtze River. In this study, we used PCR-based method to obtain the complete mtDNA of this subspecies. The arrangement pattern of the complete mtDNA is identical with typical bird species, which is the shortest (16,723 bp) in three subspecies. The length of the PCGs is same except ND2, ND3 and ND6, and the initiation/termination codons are all same with other subspecies. The length of 12S rRNA and 16S rRNA is same with C. c. columbianus, but different from C. c. bewickii. The length and structure of all tRNAs are the same with other subspecies except for tRNA(Ile), tRNA(leu(CUN)) and tRNA(ser(AGY)). The control region is located between tRNA(Phe) and tRNA(Glu), but the length is different with others.